package cn.sxt.wapperclass;

public class TestStringBuilder {
    public static void main(String[] args) {
        //StringBuilder线程不安全效率高(一般使用它)；StringBuffer线程安全，效率低
        StringBuilder sb = new StringBuilder("abcdefg");

        System.out.println(sb.hashCode());
        System.out.println(sb);
        sb.setCharAt(2,'E');
        System.out.println(sb.hashCode());
        System.out.println(sb);


    }
}
